含沙水双吸泵的结构改进与流场分析

Flow field analysis and structural improvement of double suction pump with sand water

针对双吸泵输送含沙水介质时,存在叶片磨损严重,叶轮口环附近泥沙聚集,泵效率低下的问题,传统的解决方法是增强叶片材料耐磨性能;而本文提出了减小双吸泵叶片安放角并在叶轮盖板外侧开楔形槽的新型改进方案,并使用FLUENT软件分别对改进前后的双吸泵内固液两相流场进行了数值分析.结果表明:改进后的叶轮入口附近低压区减小,增强了叶轮的抗蚀性能;叶轮流场得到改善,叶片压力面附近漩涡消失,效率提高约1.5%.减小叶片安放角可以有效降低叶片压力面进口和吸力面出口的沙粒浓度,改善叶片表面的泥沙磨损;采用楔形槽能够提高叶轮口环附近流体速度,增强水流对泥沙的携带能力,大幅度减小口环附近的沙粒体积分数,泥沙聚集减少,减缓了叶轮口环的磨损.

There are some problems of serious blade wear,sediment accumulation near impeller ring and low efficiency in the process of transporting sand-water medium by the double suction pump.The traditional solution is to enhance the wear resistance of blade material.This paper proposes a new and improved double suction pump structure,which reduces the blade placement angle and opens wedge groove on the outer side of impeller cover plate,and analyzes the flow field of solid-liquid two-phase flow in the double suction pump before and after the improvement by FLUENT.The numerical simulation results show that the low-pressure area near the improved impeller inlet decreases and the cavitation erosion resistance of the impeller is enhanced.The impeller flow field is improved,and the vortex near the pressure surface of the impeller vanishes.The efficiency is increased by about 1.5%.Decreasing the blade installation angle can effectively reduce the sand concentration at the inlet of the blade pressure surface and the outlet of the blade suction surface,and improve the sediment wear on the surface of the blade.The wedge-shaped groove can improve the fluid velocity near the impeller ,which enhances the carrying capacity of the water flow on the sediment.In addition,it can greatly reduce the sand volume fraction near the impeller ring,slowing down impeller ring wear.